// staticchecking/dr/DogsAndRobots.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// {java staticchecking.dr.DogsAndRobots}
package dr;

interface Speaks {
    void talk();
}

class Dog implements Speaks {
    public void talk() {
        System.out.println("Woof!");
    }

    public void reproduce() {
    }
}

class Robot implements Speaks {
    public void talk() {
        System.out.println("Click!");
    }

    public void oilChange() {
    }
}

class Communicate {
    public static <T extends Speaks>
    void speak(T speaker) {
        speaker.talk();
    }
}

public class DogsAndRobots {
    public static void main(String[] args) {
        Dog d = new Dog();
        Robot r = new Robot();
        Communicate.speak(d);
        Communicate.speak(r);
    }
}
/* Output:
Woof!
Click!
*/
